Electrodynamic brake.



No. 893,536. PATENTED JULY 14,' 1908. F. W. NEWELL.

ELEG'I'RODYNAMIG BRAKE.

APPLICATION FILED DEO.5,1906.

- T avwewtoz A wi cwzoocoz %/LZM 6-, mm M UNITED STATES PATENT -OFFICE. FREDERICK W. NEWELL, OF HASTINGS-UPON-HUDSON, hIEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW TERSEY, A CORPORATION OF NEW JERSEY.

ELECTRODYNAMIG Baum.

Patented July 14, 1908.

Original application filed November 18, 1905, Seria.1 No. 286,998. Divided. and this application filed December 5, 1906. Serial No; 346,391.

To all whom it may concern:

Be it knbwn that I, FREDERICK W. NEW- ELL, a citizen of the United States, residing at Hastings-upon-Hudson, in the county of Westchester and State of New York, have invented a new and useful Improvement in Electrodynamic Brakes, of which the following is a specification.

My invention relates to motor-controlling means and is a division of my application for an improvement in automatic motor-controlling apparatus, patented June 18, 1907, No. s57,1e1.

One of the objects of my invention is the provision of simple and efficient means for stopping an electric motorwhen the same is being driven as a generator.

Other objects of the invention will appear hereinafter, the novel combinations of ele ments being pointed out in the claims.

In the accompanyin drawing which represents diagrammatically a system of C11- cuits and apparatus to illustrate an a plication of the invention, 2 designates a re ay for controlling the operation of the motor M.

50 designates a main line switch, which in this instance is shown provided with manual means 62 for initially closing said switch by moving the contacts 53, 70 and 71 into engagement with the fixed contacts 52 and 72.

68 designates a brake magnet solenoid, F the shunt field of the motor, and S the series field thereof.

1 designates the starting resistance and A the accelerating magnet for controlling said resistance to vary the current flowing through the armature 31.

When the,main line switch 50 is closed, a current will flow from the +mainto contacts 52 and 53, and by way of wire 21 through solenoid 22 and wire 24 to wire 36, and thence through contacts 71 and 72 to the main. The core 23 of; the rela 2"will therefore be magnetized to attract its armature 43 against the action of the spring to move the contact 45 into engagement with the fixed contact 56. The lever 77 carrying, the armature 43 is pivoted at 44 and nor mally held in its right-hand position, as shown, by the spring 55. By the closure of the switch 50, a circuit will also be estab lished through coil 27 wire :7 6, brush 30, ar-

mature 31, brush 32, series field S, sectional resistance 1, and thence by way of wire 36 to the main. The winding 27 isof low resistance while that designated 2:2 is of comparatively high resistance, and the winding 27 is wound to normally assist the winding 22' in magnetizing the core 23]. As soon as the contacts 45' and 56 are placed in engagement with each other a circuit is closed from the point 58 through the coil 54, wire 51, ar- 1 mature lever 77, contacts 4 5 and 56, wires 57, 24 and 36, to the main. This circuit constitutes a retaining or holding circuit for the switch 50, for, as soon as the switch 50 is closed manually by means of the handle 62,

the relay '2 is operated to effect the excitation of the coil 54 which then acts on its core 59 to hold the same in its uppermost osition, and consequently the contacts 0 the switch 50 in firm engagement with each other. The movable contacts 53, 70 and 71 are insulated from each other by the bar or plate of insulation 61 to which they are secured and by which they are carried. This bar or plate 61 is rigidly attached to the upper end of the stem 60 which is carried by the core 59. When the switch 50 is closed and held closed in the manner stated, a circuit is also established from the +main throu 11 wire 63, shunt field F and wires 64 an 36 to the +main. Also a circuit is closed from the main through wire 67, brake-magnet solenoid 68,'wire '69, to the main. The excitation of the coil 68 will cause its core 73 to be lifted to release the brake B by means of the stem 74 which is connected between the core 73 and the brake shoe. The brake aparatus may be of any well known type, and the brake-applying means is in this instance shown as a spring 78 encirclin the stem 7.4 between the brake shoe and the xed bracket 79.

The motor may now start and as the counter-electro-motive force ofthe motor increases the acceleratin magnet A will receive more current to e 'ect a gradual cutting out of the resistance 1 and the series field S,

so that the 'motor may start with a strong torque as, a compound-wound-motor, an

after being started and run to full speed,

thereafter operate as a shunt wound motor.

. Should the load connected tothe motor M, as for instance an elevator car and hoisting mechanism therefor, o erate such motor as a generator, current wou dbe sent by said generator through the coil 27' in an opposite direction and thence back into the hne. Part of such current would be shunted through the coil 22, but it should be noted that when the current passes through these two coils 27 and 22' in series instead of in parallel, as normally, these coils will neutralize each others magnetism and the spring 55 will,

therefore, disengage the contacts 45', 56, and

' cation of the brake and the consequent stop relay ping of the motor in an obvious manner.

Although I have herein shown but a single form of my invention, it is obvious that those skilled in the art may make various modifications in the details and arrangement of parts without departing from the spirit and scope thereof. I desire therefore not to be limited to the exact construction herein disclosed.

What I claim is 1. The combination with a motor, of controllin apparatus therefor, a differential having a winding connected directly across the mains, and means controlled by said relay for effecting a positive stop of said motor when the same acts as a generator.

2. The combination with a motor, of an electro-magnetic main line switch therefor, a brake-ma net, a doubly-wound magnet having a win ing connected directly across the mains, and means controlledb said doublywound magnet for efiectin t e opening of the main line-switch and eenergization of said brake magnet when the motor acts as a generator.

'3. The combination with an electric motor, of a main line switch therefor, an electromagnet for holdin said main line switch clbsed, a difi'erentia relay having a windin connected directly across the mains, an

means controlled by said rela for denergizing said electro-magnet to e ect an opening of the main line switch when the motor attains an excessive speed.

4. The combination with an electric motor, of a main line switch,means for holdmg sald main line switch in closed position, a

differentially wound magnet having one winding connected across the mains and the other winding in series with the motor armature, and means controlled by said magnet for efiecting the opening of the main line switch.

5. The combination with an electric motor, of a main line switch therefor, means .for operatmg said switch, a doubly wound magnet. havlng one wlnding connected ermanently across the mains and the other windmg permanently in series with the motor armature, and means controlled by said magnet for effecting an opening of the main hne switch. i

- 6. The combination with an electric motor, of controlling apparatus therefor, a differential relay having one winding of low paratively highresistance connected directly across the mains, and means controlled by said relay for normally holding the main line same when the motor acts as a generator.

7 The combination with an electric motor, ofa main line switch and controlling apparatus for said motor, an electro -magnet for holding said main line switch closed, a brake magnet a differentially wound magnet having one winding connected between one or" the mains and the motor-armature and having the other winding connected between the two mains, and means controlled by said difierentially-wound magnet for closing the circuit for the holding electro-magnet during the normal operation of the motor and for efiecting the opening of the main line switch when the motor attains an excessive speed.

8. The combination with an electric motor, of motor-controlling apparatus, electro-magnetic brake mechanism, an electromagnetic main line switch, and a difierent al relay having its windings connected respectively directly across the mains and in series with the motor armature for controlling said main line switch and brake mechan- 18m.

9. The combination with an electric motor, of a brake magnet, a mainline switch, a brake magnet switch, a differential relay, and ,means controlled by said relay for effecting the operation of said switches.

10. The combination with an electric motor, of a brake magnet, a main line switch, a brake magnet switch, an electro-magnet for operating the main line switch and brake magnet switch, an additional switch in circuit with the last-named electro-magnet, and adoubly wound magnet controlling said lastnamed switch.

11. The combination with an electric motor comprising a shunt field winding, of a main line switch, a differentially wound magnet having a winding connected directly in parallel with the shunt field winding, and means operated by said magnet for controllin said switch.

' 12. he combination with a compound wound motor, of electro-magnetic brake .mechanism, a diflerentially wound magnet havin its windings connected in series and direct y in shunt, respectively, with the series and shunt field windings, and means operated by said magnet for controlling the brake mechanism.

. 13. The combination .with 8.11 electric resistance and the other winding of com.

circuit closed and effecting an opening of the and the deenergization of the brake-magnet motor, of brake apparatus therefor. com' prising a brake magnet, a main line switch, a magnet for controlling said main line switch, 'a differential relay controlling said magnet, and an auxiliary switch comprising an isolated contact co-acting with said main line switch to control the brake magnet- 14. The combination with an electric motor, of electro-magnetic brake apparatus. therefor, a main line switch, an isolated contact connected to the brake magnet and 00- operating with said main line switch, a otential magnet for holding the main line switch closed, and a differential relay for controlling said (potential magnet, one of the 15 name to this specification in the presence of 20 two subscribing witnesses.

FREDERICK W. NEWELL.

Witnesses:

WALTER C. STRONG, CHARLES F. WHEATON. 

